HP 48g Graphing Calculator - Manual (Page 449)

5. Press and release the “D” key (the key with D next to it).
6. Release (ON). A vertical line will appear at both sides and at the
center of the display.
7. Press and release
K'RMl or RflM2 will appear at the top left corner of the display and
the size of the corresponding plug-in RAM card (32K or 128K) will
appear at the top right corner of the display. OK will appear to the
right of KHi
completed. or RflM2 when the port RAM test has been successfully
A failure message (for example, KHtil 00092) will be displayed for
each port that does not contain a plug-in RAM card or if a card’s
read/write switch is in the “write-protect” position. This message
should be ignored.
If OK doesn’t appear for a RAM card set to read/write, the card
should be moved to the other port and the test rerun. If OK still
doesn’t appear, the RAM card should be replaced with a new one.
To return to normal calculator operation (system halt):
1. Press and hold iW|.
2. Press and release the “C” key (the key with C next to it)
3. Release (ON). The empty stack display should appear.
IR Loop-Back Test
This test checks the operation of the send and receive infrared sensors
and their associated circuits.
To run the IR loop-back test:
1. Turn on the calculator.
2. Press and hold iWj.
3. Press and release the “D” key (the key with D next to it).
4. Release
(Ml-
A vertical line will appear at both sides and at the
center of the display.
5. Be sure that the plastic plug-in card cover is in place and that it
covers the clear lamp bulbs in the top end of the calculator.
6. Pre,ss f EVAL).
Support, Batteries, and Service A-13